• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.263-268
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• 2021

Although the compact capacitance model of point tunneling types of tunneling field-effect transistors (TFET) has been proposed, those of line tunneling types of TFETs have not been reported. In this study, a compact capacitance model of an L-shaped TFET (LTFET), a line tunneling type of TFET, is proposed using the previously developed surface potentials and current models of P- and L-type LTFETs. The Verilog-A LTFET model for simulation program with integrated circuit emphasis (SPICE) was also developed to verify the validation of the compact LTFET model including the capacitance model. The SPICE simulation results using the Verilog-A LTFET were compared to those obtained using a technology computer-aided-design (TCAD) device simulator. The current-voltage characteristics and capacitance-voltage characteristics of N and P-LTFETs were consistent for all operational bias. The voltage transfer characteristics and transient response of the inverter circuit comprising N and P-LTFETs in series were verified with the TCAD mixed-mode simulation results.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.67-79
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• 2017

Increasing transportation dependence on the metro system has lead to the convenience of passengers becoming as important as the transportation capacity. In this study, a pedestrian simulator has been developed that can quantitatively assess the pedestrian environment in terms of attributes such as speed and distance. The simulator consists of modules designed for 3D indoor map authoring and algorithmic pedestrian modeling. Module functions for 3D indoor map authoring include 3D spatial modeling, network generation, and evaluation of obtained results. The pedestrian modeling algorithm executes functions such as conducting a path search, allocation of users, and evaluation of level of service (LOS). The primary objective behind developing the said functions is to apply and analyze various scenarios repeatedly, such as before and after the improvement of the pedestrian environment, and to integrate the spatial information database with the dynamic information database. Furthermore, to demonstrate the practical applicability of the proposed simulator in the future, a test-bed was constructed for a currently operational metro station and the quantitative index of the proposed improvement effect was calculated by analyzing the walking speed of pedestrians before and after the improvement of the passage. The possibility of database extension for further analysis has also been discussed in this study.

• Journal of Hydrogen and New Energy
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• v.28 no.4
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• pp.401-406
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• 2017

When Liquified Natural Gas (LNG) is vaporized into NG for industrial and household usage, tremendous cold energy was transferred from LNG to seawater during phase-changing process. This heat exchanger loop is not only a waste of huge cold energy, but will cause thermal pollution to the coastal fishery area also when cold water was re-injected into the sea. In this study, an innovation design has been performed to reclaim the cold energy for -35 to $62^{\circ}C$ refrigerated warehouse. Conventionally, this was done by installing mechanical refrigeration systems, necessitating tremendous electrical power to drive temperature. A closed loop LNG heat exchangers in series was designed to replace the mechanical or vapor-compression refrigeration cycle by process simulator. The process simulation software of PRO II with provision has been used to simulate this process for various conditions, what to effect on cold energy and used energy for re-liquefaction and evaporation process. In addition, through analysis the effect of the change of LNG supply pressure on sensible and latent heat, optimum operational conditions was suggested for LNG cold energy warehouse.

• Fire Science and Engineering
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• v.17 no.2
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• pp.62-69
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• 2003

The smoke control system in subway platform is not only using for smoke exhaust facility but also using ventilation system. For this reason, smoke vent effectiveness is depending on its position, ventilating volume capacity and the vent method. In this study, the passenger's evacuation time was calculated for the case of fire on sloped subway train vehicle in subway platform. In order to recommend the mechanical smoke exhaust operation mode, SES (Subway Environmental Simulation) was used to predict the airflow of the inlet and outlet tunnel for the subway station. Fire dynamics Simulator(FDS) was used the SES's velocity boundary conditions to calculate the smoke density and temperature under the condition of fire on stopped subway train vehicle at the platform. We compared smoke density and temperature distributions for each 6 types of smoke exhaust systems to clarify the characteristics of smoke and hot air exhaust effectiveness from the result of fire simulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.95-100
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• 2004

This paper represents the development of a CLS(Control Loading System) for a target a airplane (KT-1) with mechanical linkage reversible flight control system. The system is composed of mechanical frame, controller, sensing part to measure the force from the stick, driving system generating the reaction forces. The DS1103 DSP(Digital Signal Processor) of the dSpace Corp. was used as the controller. The control algorithm of the CLS and the operational environment including monitoring software and evaluation tools are described. The evaluation of the system was conducted according to the requirement specification. The results of the test were analyzed by comparing with the actual data of the target airplane.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.512-516
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• 2012

Recently the Korean government's green energy growth policy has been taken at the national level due to the sufficient supply of renewable energy. Some specific technique should be taken in consideration for the operation of the grid voltage and power quality management. In this case, there may have some chance of operational problems. Typical problems arise when grid-connected solar power produced by Pacific sunshine. The power flow in the reverse direction can create overvoltage on the distribution line and gives value of malfunction on the system. Line voltage and overvoltage adjustment practice can stop these symptoms occurred. Under these circumstances, this paper presents an interconnection test devices for photovoltaic(PV) systems composed of distribution system simulator, PV system simulator and control and monitoring systems using the LabVIEW S/W, and simulates the customer voltage characteristics considering the 3 parameters on the introduction capacity for PV systems, system configuration and Power factor. This paper also proposes a new calculation algorithm for voltage profile to make comparison between calculation values and test device values. The results show that the simulation results for the normal operation characteristics of PV systems which are very practical and effective.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.115-123
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• 2018

we analyzed simulation of the effectiveness for one or two DIRCM on a helicopter. The survival rate of helicopter followed increase of the deception rate of DIRCM. When the deception rate was over 70% at 100% detection rate, the survival rate was 10~30% when one DIRCM was installed and the survival rate was 70~80% when two DIRCMs were installed. When the detection rate was over 70% at 100% deception rate the survival rate was 10~30% case of one DIRCM was installed. survival rate was 20~30% when two were installed. Survival rate of 70~90% was observed with one DIRCM when the deception rate and detection rate were 100%, and 100% with two DIRCMs.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.761-765
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• 1995

The old Timing Controller for Control Element Drive Mechanism (CEDM) is designed as an open loop control system because it is difficult to mount sensors within the Control Element Drive Mechanism(CEDM) which is operating under the pressure boundary of the reactor vessel. In this work new method which can be used to detect the CEDM operational conditions without mounting sensors within the CEDM housing is developed in order to resolve problems of the old Timing Controller. By using the developed new method, the new Timing Controller for the CEDM is designed as a closed loop controller which has features of the control rod drop prevention, fine position control and the coil life time extension. The algorithm developed under closed loop control concept resolves most problems occurred in the old Timing Controller and improves the performance and reliability of the system. During designing and testing of the Timing Controller algorithm, the real time CEDM simulator developed here was used. And all functions of the developed algorithm were verified using CEDM simulator with the real data collected from the site. The results show that the Timing Controller performs its intended functions properly.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.132-140
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• 2002

By utilizing OSMI (Ocean Scanning Multi-spectral Imager) onboard KOMPSAT-1, the moon can be imaged. Because the moon has no atmosphere and reflects sun lights at a constant rate, it can be the radiance source for calibration of OSMI. But there are a lot of risks which made KOMPSAT-1 enter into safe-hold mode. So planning the imaging of the moon with OSMI should be determined seriously with consideration to information on KOMPSAT-1 operation, the moon, the sun, etc. But it takes a long time for determining the imaging time of the moon using MCE(Mission Control Element) simulator and there are operational problems to be solved. In this paper, fast simulator for determining imaging time for the moon with OSMI has been developed. The proper timeline for imaging the moon and the position of the moon image in OSMI image coordinates and the phase of the moon are determined. STK was used for acquiring information on KOMPSAT-1, the moon, the sun and the characteristitcs of OSMI are considered. As a result, we can determine imaging time of the moon with OSMI much faster and efficiently.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.460-468
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• 2020

Research related to the technology developed for the Maritime Autonomous Surface Ship (MASS) is currently underway. Although one of those core technologies is collision-avoidance technology for ship operators at sea, no research has been done to objectively quantify its effectiveness. Therefore, this study was conducted to develop an evaluation model to examine the collision-avoidance ability of MASS. Ship-control experts performed a ship-handling simulation for each ship encounter type using the Full Mission Ship-handling Simulator (FMSS). We used the resulting data and technical statistics, to develop an evaluation model that utilized FMSS to quantify the operational capability of the collision-avoidance technology. This evaluation model also can be used at sea to assess deck officers' ability to use the technology and to improve and develop other MASS technologies.